Guide for inside tubes of blasting-cartridges.



PATENTED FEB. 24, 190

l T. E. DURHAM. j GUIDE EDR INSIDE TUBES 0E RLASTTNG CARTRIDGES.

APPLIOATION FILED APE. 9, 1902.

D6 MODEL.

.wi/knee ow www UNITED STATES PATENT OFFICE.l

THOMAS F. DURHAM,.OF PHILADELPHIA,- PENNSYLVANIA.

GUIDE FOR INSIDE TUBES OVFVBLASTING-CARTRID'GES.

SPECIFICATION forming part-of Letters Patent No. 721,431, aerea February 24, 1903.

Application filed April 9, 1902. Serial No. 101,975. (No model.)

To all whom, z'ftmrtyvoncern:

Be it known that 1, THOMAS F. DURHAM, a citizen ofthe United States, residing at Philadelphia, county of Philadelphia, and Stateof Pennsylvania, have invented a certainrnew and useful Improvement in Guides for Inside rIubes ot' Blasting-Cartridges, offwhich the following is a specification.

My invention relates to a new and useful improvement in guides for inside tubes of blasting-cartridges, and has, for its object to provide an inexpensive, simple, and eective means for holding the inner tube of a safety blasting-cartridge at a distance from the outer tube, and in the space between said tubes is designed to be placed the fire-extinguishing agent. r

With these endsin View this invention consists in the detailsl of construction and combinatior of elements hereinafter set forth,- and then specically designated by the claims.

In order that those skilled in the art to which this invention appertains may understand how to make and use the same, the construction and operation will now be described in detail, referring to the accompanying drawings, formi-ng a part of this specification, in whichy Figure l is a vertical longitudinal section of ablasting-cartridge with my improvement applied thereto; Fig. 2-a sectiontaken on Astrips G used, it is obvious that more-couldv the line'Z 2 ofA Fig. 1. Y

This invention is designedy as an improvement upon patent issued to me January 21, 1902, No. 691,367, and is designedto be applied to safety blasting-cartridges' in whichv the explosive is held in a sealed inner tube, and this inner tube is then placed in an outer tube, and the innertube is held by my device at a distance from the walls of the outer tube, so that the lire-extinguishing agent may surround the innertube upon all sides.

In the drawings, A represents the outer tube, which is closed lat the lower end, and upon the inner sideof the closed lower end is secured a block or projection B, upon which the inner tubeC is adapted to rest.` The inner tube C is `also closed at the bottom and after the explosive D is inserted therein is sealed by means of a cork or plugE, through which extends the igniting d evice F. The projection B holds the inner tube at a distance from the bottom of the outer tube, and for the-purpose of holding the inner tube at a distance from the walls of the outer tube I provide near the top andbottom the bands or stripsG, which are bent into rectilinear shape, so as to form angles or corners II, which are adapted to come in contact with the walls of the outer tube A, the inner and outer tubes being circular in cross-section. Thus the strip G will come in contact with the inner tubeat four points midway between the angles or corners II, and the corners II of th'e strip coming in contact with the outer tube will hold the inner tube at an equal distance from the outer tube at all points. These bands or strips G-are secured to the inner` tube at the points where they touch such tube, and

any means may be employed for securing' these strips in place; but as I prefer to formthe outer and inner tubeof pasteboard coated with parafn glue and paraffin would be suficicnt to hold the strips to the inner tube, as they are not subjected to any longitudinal strain. The space thus formed between the inner land outer tube .is adapted to be filled ,with the ireextinguishing agent I, which may be either a liquid or gas, and' then the open end of the outer'tube A is closed by a cork or plug J, through which the wire or fuse K of the igniting device projects.

While I have .show'n two of the b,nds or be used without departing from the spirit of the invention, and also while I have shown the strip G bent into a square form, for-,ming fonrangles or corners H, it is 'also obvious that this strip or'band G could be bent into a pentagon, hexagon, Octagon, or any other form and still be within the scope of the claims, it only being necessary that the bands shall be bent so as to form angles or corners which project beyond the inner tube and hold the said innertube at a distance from the Walls of the outer tube, and while holding the inner tube in position it does not interfere with the free circulation of the re-` extinguishing agent within the outer tube. The band G need not necessarily be flat in cross-section, but maybe of anyshape desired, such as round or square. Therefore I do not wish to be limited to the exact con-A structions here shown, as slight modifications could be made Without departing from the spirit of my invention.

Having thus fully described my invention, what I claim as new and useful is 1. In a safety blasting cartridge of the character-described, an inner and outer tube, means for holding the inner tube at a distance from the outer tube, said means consisting of a band or strip bent into a polygonal form and surrounding the inner tube, the angles i or corners formed by the bending of the strip adapted to protrude beyond the inner tube and come in contact with thevinside of the outer tube, as and for the purpose specified.

2. In a safety blasting-cartridge of the character described consisting of an inner and outer tube, both circular in cross-section,

means for holding the inner tube at a distance from the outer tube, said means consisting of a strip or band bent so as to form a plurality of angles or corners, which angles or corners project beyond the inner tube and are adapted to come in contact with the outer tube, said band lbeing secured to the inner tube at points midway between the angles or corners, as and for the purpose specified.

.In testimony whereof I have hereunto affixed my signature in the presence of two subscribing witnesses.

THOMAS F. DURHAM. Witnesses:

H. B. HALLooK, L. W. MORRISON. 

